ULT-100 Ultrasonic level transmitter

Learn About: Magnetostrictive level transmitter

Magnetostrictive level sensor

Extended reading: Guide to Ultrasonic Level Transmitters

Ultrasonic level transmitter working principle

Ultrasonic waves propagate in gases, liquids, and solids and have a certain propagation speed. Ultrasonic waves will be absorbed and attenuated when propagating in the medium. The attenuation of propagation in gas is the largest. The attenuation of propagation in solids is the smallest.

Ultrasound will reflect and refract when passing through the interface of two different media. For interfaces with large acoustic impedances, it is almost totally reflected. The time interval from transmitting the ultrasonic wave to receiving the transmitted signal is related to the position of the interface. The ultrasonic liquid level meter uses this feature of the ultrasonic wave for level measurement.

The transmitter and receiver of the Ultrasonic level transmitter can be installed on the bottom of the container or on the top of the container. The transmitted ultrasonic waves are emitted at the phase interface and received by the receiver. The time interval between the ultrasonic waves received from the transmitter is measured. You can measure the level of the level.

Ultrasonic level transmitters can be divided into three types: solid-medium, air-medium, and liquid-medium according to different sound transmission media. According to the working mode of the probe, it can be divided into the self-transmitting and self-receiving single probe method and the dual-probe method with separate transmission and reception. Combine with each other to get 6 kinds of ultrasonic level gauges.

In the actual measurement, sometimes there will be bubbles, suspended matter, waves or liquid boiling on the liquid surface, causing confusion in reflection and measurement errors. Therefore, solid-medium level gauges should be used in complex situations. Figure 1 is a single-probe ultrasonic level gauge. It uses a transducer, which is controlled by a control circuit, and alternately works as a transmitter and a receiver in time-sharing.

Suppose the distance from the ultrasonic wave to the liquid surface is H, the wave propagation speed is c, and the propagation time interval is △t, then: H=c△t/2

Extended reading: Radar level sensor for solids – Dust solid level measurement

Extended reading: What is the difference between ultrasonic and radar level transmitters?

Ultrasonic level transmitter calibration procedure

The propagation speed of ultrasonic waves in the air is 340m/s. If the propagation time of ultrasonic waves in the air can be measured, the distance of propagation can be calculated.

Ultrasonic measurement of liquid level is to measure the distance of sound wave transmission by measuring the time gap of ultrasonic wave propagation.

Specific method: see the picture above.

An ultrasonic probe mounted on the top of the container under test emits a beam of ultrasonic waves to the liquid surface. After the sound wave is reflected by the liquid surface, it is received by the probe.

The controller measures the propagation time t, according to the speed of sound v=340m/s. The spatial distance L from the liquid level to the probe can be obtained. The distance between the probe and the bottom of the container is H, and the height of the liquid level in the container is h.

The calculation formula is: h=H-L where L=v×t/2

Since temperature has an effect on the speed of sound, the air temperature T needs to be measured to correct the speed of sound.

The correction formula is: v=331.46×T (℃)

B is the blind zone. The blind zone means that the reflected echo cannot be detected normally at a short distance from the bottom of the ultrasonic probe. This small distance is called the blind zone of the ultrasonic level gauge.

The reflected wave cannot be detected normally within this small distance. That’s because the ultrasonic level gauge emits ultrasonic pulses. The reflected echo cannot be detected at the same time.

And because the transmitted ultrasonic pulse has a certain time width. And the sensor still has after-vibration after transmitting the ultrasonic wave. During this period, the ultrasonic level gauge cannot detect the reflected echo.

When measuring the liquid level, if the highest liquid level to be measured enters the blind zone. The ultrasonic level gauge will not be able to correctly detect the actual height of the liquid level. There will be errors. When encountering similar situations, you can install the level gauge higher or lower the liquid level as needed.

So the ultrasonic liquid level measurement range is: 0～(H-B)

Read more about: What Is the Difference Between Class 1 Div 1 and Class 1 Div 2 ?

Featured ultrasonic level sensor for tanks

What is the advantage of ultrasonic level measurement system?

Ultrasonic level transmitter is an ideal measurement tool for corrosive, junctional or acid-base wastewater. Ultrasonic level transmitter can measure the media including hydrochloric acid, sulfuric acid, hydroxide, waste water, resin, paraffin, mud, lye and bleach and other industrial agents.

Compared with other level gauges, Ultrasonic level transmitter also has the following advantages:

• Non-contact measurement.
• No moving parts, simple structure and long service life.
• Corrosion resistance (most of the probes are made of PVDF, PP and other materials).
• Automatic temperature compensation function.
• Not affected by the humidity and viscosity of the medium.
• Not affected by dielectric constant, electrical conductivity, and thermal conductivity of the medium.
• Excellent cost performance.

Extended reading: Non Contact Liquid Level Sensor Working Principle

What is the difference between ultrasonic and radar level transmitters?

Radar level transmitter and Ultrasonic level transmitter are both liquid level measuring instruments. The most obvious difference is that one uses electromagnetic waves and the other uses ultrasonic waves. So, besides that, what is the difference between a Radar level transmitter and an Ultrasonic level transmitter?

Read More about Ultrasonic level transmitter VS Radar level transmitter

Extended reading: Radar Liquid Level Sensor|Corrosive, steam, volatile liquids

How to choose explosion-proof Ultrasonic level transmitter?

The ultrasonic level transmitter has explosion-proof and non-explosion-proof. Then the model selection of ultrasonic level gauge is different according to different working conditions. The explosion-proof type is subdivided into two types: intrinsically safe explosion-proof and explosion-proof. Explosion-proof means to assemble and fix the components, and use a stainless steel host outside. Intrinsically safe explosion-proof is to seal all the components and isolate the explosive gas outside the cavity. More about Factors To Consider When Choosing Explosion Proof Ultrasonic Level Sensors.

Ultrasonic level transmitter is a level gauge that is more commonly used to measure various material levels and liquid levels. It is divided into two types: one-piece and split-type. One-piece ultrasonic level gauge, optional two-wire or four-wire, two-wire The system can only supply 24VDC, 4-20mA current loop. Non-contact continuous measurement reduces maintenance and is cost-effective.

1. The measured medium is flammable and explosive, mostly liquid and gas. For example: gasoline, alcohol, toluene, xylene, acetone, biogas, gas, hydrogen, etc., most of which are organic compounds. Solid: There are metallic magnesium, metallic sodium, yellow phosphorus and so on.
2. Underground mines, including coal mines, iron mines, etc., almost all mines need explosion-proof ultrasonic level gauges.
3. Places with heavy dust, such as wood processing workshops; coal processing workshops; dusts reaching a certain concentration can also cause explosions.
4. Although there is no direct contact with flammable and explosive liquids and gases, but in explosion-proof areas, explosion-proof ultrasonic level gauges and ultrasonic level gauges are also required. For example: the fire-fighting pool in the tank farm.

In the above four cases, it is necessary to install an explosion-proof Ultrasonic level transmitter, so as to avoid the existence of potential safety hazards.

Read more: Guide: Non-contact Ultrasonic Level Sensing transmitters

Ultrasonic level transmitter price

Ultrasonic level transmitter price is determined by the following parameters.

1. The type of medium being measured: liquid or solid.
   Specific name: clean water, sewage, mud, gasoline, diesel, toluene, sulfur dioxide, etc.
   If it is a liquid: whether there is steam, mist, foam, waves, stirring, or floating objects on the liquid surface.
   If it is solid: whether there is dust.
2. The minimum to maximum temperature and the minimum to maximum pressure of the medium.
3. The corrosiveness of the medium. If it is placed in a tank, it is necessary to know the material of the tank and whether there is an anticorrosive lining.
4. 4.Whether explosion-proof and anti-corrosion are required.
5. The measurement range is a few meters, and what is the required blind zone.
6. Working environment: such as open pools, pools with lids, horizontal tanks, standing tanks, spherical tanks, whether the tanks are at atmospheric pressure, etc.
7. Working voltage: 24VDC or 220VAC
8. Output signal: 4～20mA current 485 communication output relay output
9. Equipment form: integrated

More tank level measurement solutions

Sino-Inst offers 20 Ultrasonic level transmitters. About 13% of these are explosion-proof ultrasonic level transmitters, 4% are ultrasonic level sensors.

A wide variety of ultrasonic level transmitter options are available to you, such as free samples, paid samples.

Sino-Inst is ultrasonic level transmitter suppliers, located in China.

Ultrasonic level transmitter products are most popular in North America, Mid East, and Eastern Europe.

The United States, and India, which export 99%, 1%, and 1% of ultrasonic level transmitter respectively.

You can ensure product safety by selecting from a certified supplier, with ISO9001, ISO14001 certification.

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